Editor's Note: Today's stories are the second installment in a series of online and broadcast reports on adoption by Reuters and NBC News.

A Texas teenager says that after her adoptive parents gave her away at age 13 to a couple they’d met over the Internet, her new “mom” made an unusual request.

“The first night I had to sleep with the woman, in the same bed with her,” recalled Anna Barnes, now 18. “That was weird, and she wasn’t clothed.”

Anna Barnes is one of the adopted children who was “re-homed” as part of America’s underground child exchange. An investigation by Reuters in partnership with NBC News has uncovered a vast network of adoptive parents who transfer unwanted children – often foreign adoptees – to virtual strangers they meet online in a range of chat rooms.

No law explicitly covers the practice of private “re-homing.” The primary safeguard that does exist is a feeble deterrent - an agreement between U.S. states called the Interstate Compact on the Placement of Children (ICPC).Although the ICPC has been adopted as law by each state, some states attach no penalties to violations of the pact. In others, violations are considered misdemeanors, but even then officials almost never prosecute offenders.

For parents who know about the compact but choose to ignore it, any legal risk is outweighed by the need to remove a troublesome child. When the underground network is used, a transfer will likely go unnoticed by authorities, minimizing the chance of getting caught.

In August 2008, Anna Barnes was 13. She had already been re-homed once since she was adopted in Russia and brought to the United States at age 7.

Her second set of American parents, Gary and Lisa Barnes of Tolar, Texas, had come to regret adopting Anna. They had talked with her original adoptive parents before taking custody. But the Barneses quickly suspected that they hadn’t been told enough about the emotional and behavioral problems Anna brought to America.

“This is a bad analogy, but it’s sort of like selling a used car,” Gary Barnes says of why he and his wife weren’t told more. “If you tell someone it breaks down every day, nobody’s going to buy it.”

The Barneses, who breed miniature horses for a living, found Anna to be defiant. Counseling proved too expensive and inconvenient. A home for troubled kids told them she wasn’t a good fit for its program. If they turned Anna over to the state of Texas, the Barneses say they were told, they would be considered unfit parents and have to pay child support until she turned 18.

“We spent the first year trying to help the child and fix the problem,” Gary says. “Then a light comes on and you realize you can’t fix the problem, that you need to get away from the problem.”

The Barneses wrote an ad about Anna and posted it online, in a Yahoo forum called Respite-Rehoming.

A woman named Nicole Eason, who was going by the name Momma Bear online, replied. In emails with the Barneses, she pledged that she and her husband Calvin were prepared to care for Anna.

“We will love her no matter what mistakes she makes in life,” Momma Bear assured the Barneses. She promised to buy Anna her favorite candy - Heath bars - and give her a puppy.

To help clinch the deal, Nicole shared a fictitious “home study” she created. In it, a social worker purportedly vouched for the Easons’ parenting skills.

It was September 2008. The Easons, then living in Westville, Ill., headed south to collect Anna. They flew some 900 miles and drove to the Barnes’s farm in Tolar, population 700.

As the five of them ate dinner at a local chain restaurant, Anna studied the Easons. They made her nervous.

When the Barneses sent Anna home with the Easons, no lawyers or government authorities were involved. No one carefully checked out the Easons or the home study they presented.

The Barneses and the Easons also didn’t inform child welfare officials that Anna was being sent from Texas to Illinois. That failure to involve authorities is a violation of the ICPC. Texas considers violations a misdemeanor. So does Illinois, although an official there says the state hasn’t prosecuted anyone for breaking the law for at least 15 years. The Barneses say they had never heard of the requirement.

In an email to Nicole shortly after the handover, Lisa wrote of the day they gave their daughter to the Easons: “When we left Gary said ‘what do we do’… I said ‘get in the car and go’ and don’t look back.”

Lisa added: “I hope she’s okay.”

NICOLE’S BED

When Anna arrived at the Eason place, she says, urine and feces spotted the floor; two puppies had been left alone in the trailer. Anna says the Easons showed her pictures of a young boy and girl who they said had once lived with them. She asked what became of them.

“Their answer to my question was, ‘Sometimes kids just die, and they both had died,’” Anna recalls. Nicole says she doesn’t remember which children she showed Anna that day.

When Nicole encouraged Anna to pick out a movie, Anna says she found pornographic films when she opened a cabinet. Nicole says there was no pornography in the house.

Anna realized she had no bed of her own. The first night, she slept next to a naked Nicole, she recalls. The next morning, she says, Nicole asked Anna if she had felt Nicole kissing her during the night.

She later was expected to sleep between Calvin and Nicole, Anna says. “I was sandwiched in there, and I stayed there for about a total of 2 minutes, 47 seconds, and decided that it was getting weird,” she recalls. She says she quickly left their room and slept on the couch.

Calvin and Nicole say they have never shared their bed with any children they took through re-homing. Nicole also says she never sleeps nude.

Anna’s heart lifted the next day at school when she saw a man with a cowboy hat in the hall. It was Gary Barnes, the adoptive father who had given her to the Easons a few days before.

The previous day, Barnes says he had been contacted by a former friend of Nicole’s. The woman thought Nicole may have responded to the ad for Anna. She believed the Easons’ home study was fabricated, Barnes says, and that authorities had removed at least one re-homed child from their custody. Barnes says the woman told him she was worried for Anna’s safety.

Now, Barnes was, too. He flew to Illinois and headed to the school Anna was to attend in Westville. To his relief, she was there.

Barnes recalls talking with school administrators, then to local police. He explained that he had come to retrieve his adopted daughter after learning the Easons had lied, law enforcement and child welfare records show.

When he and Anna returned to Tolar, Barnes filed a complaint about the Easons with the Texas Attorney General’s office.

The attorney general also heard from Lynne Banks, an adoptive mother in South Dakota who monitored the online re-homing groups and had grown concerned about the Easons.

In a Sept. 10, 2008, email to the Texas Attorney General’s office, Banks reported that the Easons had already succeeded in taking four children.

“Nicole seems to be in the practice of luring in adoptive parents who are looking to disrupt their adoptions and taking their children by using false documentation,” Banks wrote.

Despite the involvement of authorities in Illinois and the warnings to authorities in Texas, the states took no steps to prevent the Easons from taking other children.

Anna Barnes, 18, recently graduated from high school. She was admitted to Texas Tech University but doesn’t think she can afford to attend. She stays with friends and is looking for a place to live.

Megan Twohey is an investigative reporter at Reuters. Kate Snow is a national correspondent for NBC News. Monica Alba is an associate producer at NBC News. Additional reporting by Ryan McNeill, Robin Respaut and Blake Morrison at Reuters.